3 1/6 +2 1/8 - 1.25
I'm going to make all these numbers into improper fraction by multiplying the whole number by the denominator and adding the numerator, for the 2 fractions, and for the '1.25' I will multiply it by 100 for the numerator and then make the denominator 100 and then simplifying, in numbers that is:
19/6+17/8-125/100
19 and 6 don't have common factors, neither do 17 and 8; but 125 and 100 do, both parts of the last fraction can be divided by 25 to make 5/4 so now the equation is:
19/6+17/8-5/4
Now we need a common denominator and I'll you 24.
76/24+51/24-30/24
Now we do the calculations, we'll leave out the denominator at the moment for ease.
76+51-30
127-30
93
That is 93/24 which can be simplified by dividing both by 3 to become:
31/8 as a mixed number that is 3 7/8 and as a decimal is 3.875
Hope this helps :)